PyTorch 1.3 Support (#426)

* summary_graph.py:
  * Change ONNX op.uniqueName() to op.debugName()
  * Removed scope-naming workaround which isn't needed in PyTorch 1.3
* Tests:
  * Naming of trace entries changed in 1.3. Fixed SummaryGraph unit
    test that checked that
  * Adjusted expected values in full_flow_tests
  * Adjusted tolerance in test_sim_bn_fold
  * Filter some new warnings